The sticks of plastic material provided with one or two end cotton buds, presently used, constitute a serious problem for water purification facilities because they are often disposed of through the drainage system, causing the obstruction of the filters of such facilities and a visual pollution of water and soil caused by the purified water and active sewage sludges which contain them.
At present, said plastic sticks are obtained by means of an extrusion technology according to which small tubes of approximately 2.5-3 mm of diameter are extruded at extrusion rates of 50-100 m/minute.
The resulting productivity is of approximately 700-1300 sticks per minute. The extruded tube is then calibrated by causing it to run first through a duct, after being sprayed with water, and then through a water bath, before being cut.
This technology is difficultly applied to the preparation of water dispersible sticks based on natural or synthetic water-soluble polymeric substances because water calibration and cooling would become unfeasible and the productivity would furthermore result very limited with air cooling.